1. Field
Embodiments of the present invention relate to an electronic parking brake system and a method of controlling the same, and more particularly, to an electronic parking brake system which controls the applying or releasing of an electronic parking brake and a method of controlling the system.
2. Description of the Related Art
Recently, electronic parking brake (EPB) systems which electronically control an operation of a parking brake are used, each of which is mounted on a general disc brake and performs a function of a parking brake.
In the case of electronic parking brake systems, even when a driver does not manually apply a parking brake, the parking brake may be automatically applied or released depending on the control determination of an electronic control unit which simply operates a switch or performs overall control.
Such electronic parking brake systems each include an EPB actuator including a motor which generates braking power and an electronic control unit for driving the EPB actuator.
The electronic control unit applies or releases the parking brake by driving the EPB actuator depending on an operation state of a switch.
EPB systems which generate parking brake power using the power of a motor determine an amount of force applied to calipers according to an amount of current generated at the motor.
When an amount of current generated while applying the parking brake is a preset value or more, it is determined that parking is completed.
When the applying of the parking brake is performed in a state in which mechanical insertion of a motor occurs, the motor cannot be driven. This phenomenon is called motor stuck.
When the motor stuck occurs, there is no actual amount of force applied to calipers but an amount of current is relatively highly generated. Here, the current is called a stall current.
Accordingly, since it is generally determined using an amount of current generated at a motor that the applying of the parking brake is completed, a stall current threshold value may also be lower than a target current range. However, when the stall current threshold value falls within the target current range, even when a motor stuck failure occurs, it may be incorrectly determined that the applying of the parking brake is normally completed.